//
// Created by SkySeraph on 2016/1/28.
//

/*************************** HEADER FILES ***************************/
#include <stdlib.h>
#include <algorithm>
#include "aes.h"

/****************************** MACROS ******************************/
// The least significant byte of the word is rotated to the end.
#define KE_ROTWORD(x) (((x) << 8) | ((x) >> 24))

#define TRUE  1
#define FALSE 0

/**************************** VARIABLES *****************************/
// This is the specified AES SBox. To look up a substitution value, put the first
// nibble in the first index (row) and the second nibble in the second index (column).
static const BYTE aes_sbox[16][16] = {
        {0x63,0x7C,0x77,0x7B,0xF2,0x6B,0x6F,0xC5,0x30,0x01,0x67,0x2B,0xFE,0xD7,0xAB,0x76},
        {0xCA,0x82,0xC9,0x7D,0xFA,0x59,0x47,0xF0,0xAD,0xD4,0xA2,0xAF,0x9C,0xA4,0x72,0xC0},
        {0xB7,0xFD,0x93,0x26,0x36,0x3F,0xF7,0xCC,0x34,0xA5,0xE5,0xF1,0x71,0xD8,0x31,0x15},
        {0x04,0xC7,0x23,0xC3,0x18,0x96,0x05,0x9A,0x07,0x12,0x80,0xE2,0xEB,0x27,0xB2,0x75},
        {0x09,0x83,0x2C,0x1A,0x1B,0x6E,0x5A,0xA0,0x52,0x3B,0xD6,0xB3,0x29,0xE3,0x2F,0x84},
        {0x53,0xD1,0x00,0xED,0x20,0xFC,0xB1,0x5B,0x6A,0xCB,0xBE,0x39,0x4A,0x4C,0x58,0xCF},
        {0xD0,0xEF,0xAA,0xFB,0x43,0x4D,0x33,0x85,0x45,0xF9,0x02,0x7F,0x50,0x3C,0x9F,0xA8},
        {0x51,0xA3,0x40,0x8F,0x92,0x9D,0x38,0xF5,0xBC,0xB6,0xDA,0x21,0x10,0xFF,0xF3,0xD2},
        {0xCD,0x0C,0x13,0xEC,0x5F,0x97,0x44,0x17,0xC4,0xA7,0x7E,0x3D,0x64,0x5D,0x19,0x73},
        {0x60,0x81,0x4F,0xDC,0x22,0x2A,0x90,0x88,0x46,0xEE,0xB8,0x14,0xDE,0x5E,0x0B,0xDB},
        {0xE0,0x32,0x3A,0x0A,0x49,0x06,0x24,0x5C,0xC2,0xD3,0xAC,0x62,0x91,0x95,0xE4,0x79},
        {0xE7,0xC8,0x37,0x6D,0x8D,0xD5,0x4E,0xA9,0x6C,0x56,0xF4,0xEA,0x65,0x7A,0xAE,0x08},
        {0xBA,0x78,0x25,0x2E,0x1C,0xA6,0xB4,0xC6,0xE8,0xDD,0x74,0x1F,0x4B,0xBD,0x8B,0x8A},
        {0x70,0x3E,0xB5,0x66,0x48,0x03,0xF6,0x0E,0x61,0x35,0x57,0xB9,0x86,0xC1,0x1D,0x9E},
        {0xE1,0xF8,0x98,0x11,0x69,0xD9,0x8E,0x94,0x9B,0x1E,0x87,0xE9,0xCE,0x55,0x28,0xDF},
        {0x8C,0xA1,0x89,0x0D,0xBF,0xE6,0x42,0x68,0x41,0x99,0x2D,0x0F,0xB0,0x54,0xBB,0x16}
};

static const BYTE aes_invsbox[16][16] = {
        {0x52,0x09,0x6A,0xD5,0x30,0x36,0xA5,0x38,0xBF,0x40,0xA3,0x9E,0x81,0xF3,0xD7,0xFB},
        {0x7C,0xE3,0x39,0x82,0x9B,0x2F,0xFF,0x87,0x34,0x8E,0x43,0x44,0xC4,0xDE,0xE9,0xCB},
        {0x54,0x7B,0x94,0x32,0xA6,0xC2,0x23,0x3D,0xEE,0x4C,0x95,0x0B,0x42,0xFA,0xC3,0x4E},
        {0x08,0x2E,0xA1,0x66,0x28,0xD9,0x24,0xB2,0x76,0x5B,0xA2,0x49,0x6D,0x8B,0xD1,0x25},
        {0x72,0xF8,0xF6,0x64,0x86,0x68,0x98,0x16,0xD4,0xA4,0x5C,0xCC,0x5D,0x65,0xB6,0x92},
        {0x6C,0x70,0x48,0x50,0xFD,0xED,0xB9,0xDA,0x5E,0x15,0x46,0x57,0xA7,0x8D,0x9D,0x84},
        {0x90,0xD8,0xAB,0x00,0x8C,0xBC,0xD3,0x0A,0xF7,0xE4,0x58,0x05,0xB8,0xB3,0x45,0x06},
        {0xD0,0x2C,0x1E,0x8F,0xCA,0x3F,0x0F,0x02,0xC1,0xAF,0xBD,0x03,0x01,0x13,0x8A,0x6B},
        {0x3A,0x91,0x11,0x41,0x4F,0x67,0xDC,0xEA,0x97,0xF2,0xCF,0xCE,0xF0,0xB4,0xE6,0x73},
        {0x96,0xAC,0x74,0x22,0xE7,0xAD,0x35,0x85,0xE2,0xF9,0x37,0xE8,0x1C,0x75,0xDF,0x6E},
        {0x47,0xF1,0x1A,0x71,0x1D,0x29,0xC5,0x89,0x6F,0xB7,0x62,0x0E,0xAA,0x18,0xBE,0x1B},
        {0xFC,0x56,0x3E,0x4B,0xC6,0xD2,0x79,0x20,0x9A,0xDB,0xC0,0xFE,0x78,0xCD,0x5A,0xF4},
        {0x1F,0xDD,0xA8,0x33,0x88,0x07,0xC7,0x31,0xB1,0x12,0x10,0x59,0x27,0x80,0xEC,0x5F},
        {0x60,0x51,0x7F,0xA9,0x19,0xB5,0x4A,0x0D,0x2D,0xE5,0x7A,0x9F,0x93,0xC9,0x9C,0xEF},
        {0xA0,0xE0,0x3B,0x4D,0xAE,0x2A,0xF5,0xB0,0xC8,0xEB,0xBB,0x3C,0x83,0x53,0x99,0x61},
        {0x17,0x2B,0x04,0x7E,0xBA,0x77,0xD6,0x26,0xE1,0x69,0x14,0x63,0x55,0x21,0x0C,0x7D}
};

// This table stores pre-calculated values for all possible GF(2^8) calculations.This
// table is only used by the (Inv)MixColumns steps.
// USAGE: The second index (column) is the coefficient of multiplication. Only 7 different
// coefficients are used: 0x01, 0x02, 0x03, 0x09, 0x0b, 0x0d, 0x0e, but multiplication by
// 1 is negligible leaving only 6 coefficients. Each column of the table is devoted to one
// of these coefficients, in the ascending order of value, from values 0x00 to 0xFF.
static const BYTE gf_mul[256][6] = {
        {0x00,0x00,0x00,0x00,0x00,0x00},{0x02,0x03,0x09,0x0b,0x0d,0x0e},
        {0x04,0x06,0x12,0x16,0x1a,0x1c},{0x06,0x05,0x1b,0x1d,0x17,0x12},
        {0x08,0x0c,0x24,0x2c,0x34,0x38},{0x0a,0x0f,0x2d,0x27,0x39,0x36},
        {0x0c,0x0a,0x36,0x3a,0x2e,0x24},{0x0e,0x09,0x3f,0x31,0x23,0x2a},
        {0x10,0x18,0x48,0x58,0x68,0x70},{0x12,0x1b,0x41,0x53,0x65,0x7e},
        {0x14,0x1e,0x5a,0x4e,0x72,0x6c},{0x16,0x1d,0x53,0x45,0x7f,0x62},
        {0x18,0x14,0x6c,0x74,0x5c,0x48},{0x1a,0x17,0x65,0x7f,0x51,0x46},
        {0x1c,0x12,0x7e,0x62,0x46,0x54},{0x1e,0x11,0x77,0x69,0x4b,0x5a},
        {0x20,0x30,0x90,0xb0,0xd0,0xe0},{0x22,0x33,0x99,0xbb,0xdd,0xee},
        {0x24,0x36,0x82,0xa6,0xca,0xfc},{0x26,0x35,0x8b,0xad,0xc7,0xf2},
        {0x28,0x3c,0xb4,0x9c,0xe4,0xd8},{0x2a,0x3f,0xbd,0x97,0xe9,0xd6},
        {0x2c,0x3a,0xa6,0x8a,0xfe,0xc4},{0x2e,0x39,0xaf,0x81,0xf3,0xca},
        {0x30,0x28,0xd8,0xe8,0xb8,0x90},{0x32,0x2b,0xd1,0xe3,0xb5,0x9e},
        {0x34,0x2e,0xca,0xfe,0xa2,0x8c},{0x36,0x2d,0xc3,0xf5,0xaf,0x82},
        {0x38,0x24,0xfc,0xc4,0x8c,0xa8},{0x3a,0x27,0xf5,0xcf,0x81,0xa6},
        {0x3c,0x22,0xee,0xd2,0x96,0xb4},{0x3e,0x21,0xe7,0xd9,0x9b,0xba},
        {0x40,0x60,0x3b,0x7b,0xbb,0xdb},{0x42,0x63,0x32,0x70,0xb6,0xd5},
        {0x44,0x66,0x29,0x6d,0xa1,0xc7},{0x46,0x65,0x20,0x66,0xac,0xc9},
        {0x48,0x6c,0x1f,0x57,0x8f,0xe3},{0x4a,0x6f,0x16,0x5c,0x82,0xed},
        {0x4c,0x6a,0x0d,0x41,0x95,0xff},{0x4e,0x69,0x04,0x4a,0x98,0xf1},
        {0x50,0x78,0x73,0x23,0xd3,0xab},{0x52,0x7b,0x7a,0x28,0xde,0xa5},
        {0x54,0x7e,0x61,0x35,0xc9,0xb7},{0x56,0x7d,0x68,0x3e,0xc4,0xb9},
        {0x58,0x74,0x57,0x0f,0xe7,0x93},{0x5a,0x77,0x5e,0x04,0xea,0x9d},
        {0x5c,0x72,0x45,0x19,0xfd,0x8f},{0x5e,0x71,0x4c,0x12,0xf0,0x81},
        {0x60,0x50,0xab,0xcb,0x6b,0x3b},{0x62,0x53,0xa2,0xc0,0x66,0x35},
        {0x64,0x56,0xb9,0xdd,0x71,0x27},{0x66,0x55,0xb0,0xd6,0x7c,0x29},
        {0x68,0x5c,0x8f,0xe7,0x5f,0x03},{0x6a,0x5f,0x86,0xec,0x52,0x0d},
        {0x6c,0x5a,0x9d,0xf1,0x45,0x1f},{0x6e,0x59,0x94,0xfa,0x48,0x11},
        {0x70,0x48,0xe3,0x93,0x03,0x4b},{0x72,0x4b,0xea,0x98,0x0e,0x45},
        {0x74,0x4e,0xf1,0x85,0x19,0x57},{0x76,0x4d,0xf8,0x8e,0x14,0x59},
        {0x78,0x44,0xc7,0xbf,0x37,0x73},{0x7a,0x47,0xce,0xb4,0x3a,0x7d},
        {0x7c,0x42,0xd5,0xa9,0x2d,0x6f},{0x7e,0x41,0xdc,0xa2,0x20,0x61},
        {0x80,0xc0,0x76,0xf6,0x6d,0xad},{0x82,0xc3,0x7f,0xfd,0x60,0xa3},
        {0x84,0xc6,0x64,0xe0,0x77,0xb1},{0x86,0xc5,0x6d,0xeb,0x7a,0xbf},
        {0x88,0xcc,0x52,0xda,0x59,0x95},{0x8a,0xcf,0x5b,0xd1,0x54,0x9b},
        {0x8c,0xca,0x40,0xcc,0x43,0x89},{0x8e,0xc9,0x49,0xc7,0x4e,0x87},
        {0x90,0xd8,0x3e,0xae,0x05,0xdd},{0x92,0xdb,0x37,0xa5,0x08,0xd3},
        {0x94,0xde,0x2c,0xb8,0x1f,0xc1},{0x96,0xdd,0x25,0xb3,0x12,0xcf},
        {0x98,0xd4,0x1a,0x82,0x31,0xe5},{0x9a,0xd7,0x13,0x89,0x3c,0xeb},
        {0x9c,0xd2,0x08,0x94,0x2b,0xf9},{0x9e,0xd1,0x01,0x9f,0x26,0xf7},
        {0xa0,0xf0,0xe6,0x46,0xbd,0x4d},{0xa2,0xf3,0xef,0x4d,0xb0,0x43},
        {0xa4,0xf6,0xf4,0x50,0xa7,0x51},{0xa6,0xf5,0xfd,0x5b,0xaa,0x5f},
        {0xa8,0xfc,0xc2,0x6a,0x89,0x75},{0xaa,0xff,0xcb,0x61,0x84,0x7b},
        {0xac,0xfa,0xd0,0x7c,0x93,0x69},{0xae,0xf9,0xd9,0x77,0x9e,0x67},
        {0xb0,0xe8,0xae,0x1e,0xd5,0x3d},{0xb2,0xeb,0xa7,0x15,0xd8,0x33},
        {0xb4,0xee,0xbc,0x08,0xcf,0x21},{0xb6,0xed,0xb5,0x03,0xc2,0x2f},
        {0xb8,0xe4,0x8a,0x32,0xe1,0x05},{0xba,0xe7,0x83,0x39,0xec,0x0b},
        {0xbc,0xe2,0x98,0x24,0xfb,0x19},{0xbe,0xe1,0x91,0x2f,0xf6,0x17},
        {0xc0,0xa0,0x4d,0x8d,0xd6,0x76},{0xc2,0xa3,0x44,0x86,0xdb,0x78},
        {0xc4,0xa6,0x5f,0x9b,0xcc,0x6a},{0xc6,0xa5,0x56,0x90,0xc1,0x64},
        {0xc8,0xac,0x69,0xa1,0xe2,0x4e},{0xca,0xaf,0x60,0xaa,0xef,0x40},
        {0xcc,0xaa,0x7b,0xb7,0xf8,0x52},{0xce,0xa9,0x72,0xbc,0xf5,0x5c},
        {0xd0,0xb8,0x05,0xd5,0xbe,0x06},{0xd2,0xbb,0x0c,0xde,0xb3,0x08},
        {0xd4,0xbe,0x17,0xc3,0xa4,0x1a},{0xd6,0xbd,0x1e,0xc8,0xa9,0x14},
        {0xd8,0xb4,0x21,0xf9,0x8a,0x3e},{0xda,0xb7,0x28,0xf2,0x87,0x30},
        {0xdc,0xb2,0x33,0xef,0x90,0x22},{0xde,0xb1,0x3a,0xe4,0x9d,0x2c},
        {0xe0,0x90,0xdd,0x3d,0x06,0x96},{0xe2,0x93,0xd4,0x36,0x0b,0x98},
        {0xe4,0x96,0xcf,0x2b,0x1c,0x8a},{0xe6,0x95,0xc6,0x20,0x11,0x84},
        {0xe8,0x9c,0xf9,0x11,0x32,0xae},{0xea,0x9f,0xf0,0x1a,0x3f,0xa0},
        {0xec,0x9a,0xeb,0x07,0x28,0xb2},{0xee,0x99,0xe2,0x0c,0x25,0xbc},
        {0xf0,0x88,0x95,0x65,0x6e,0xe6},{0xf2,0x8b,0x9c,0x6e,0x63,0xe8},
        {0xf4,0x8e,0x87,0x73,0x74,0xfa},{0xf6,0x8d,0x8e,0x78,0x79,0xf4},
        {0xf8,0x84,0xb1,0x49,0x5a,0xde},{0xfa,0x87,0xb8,0x42,0x57,0xd0},
        {0xfc,0x82,0xa3,0x5f,0x40,0xc2},{0xfe,0x81,0xaa,0x54,0x4d,0xcc},
        {0x1b,0x9b,0xec,0xf7,0xda,0x41},{0x19,0x98,0xe5,0xfc,0xd7,0x4f},
        {0x1f,0x9d,0xfe,0xe1,0xc0,0x5d},{0x1d,0x9e,0xf7,0xea,0xcd,0x53},
        {0x13,0x97,0xc8,0xdb,0xee,0x79},{0x11,0x94,0xc1,0xd0,0xe3,0x77},
        {0x17,0x91,0xda,0xcd,0xf4,0x65},{0x15,0x92,0xd3,0xc6,0xf9,0x6b},
        {0x0b,0x83,0xa4,0xaf,0xb2,0x31},{0x09,0x80,0xad,0xa4,0xbf,0x3f},
        {0x0f,0x85,0xb6,0xb9,0xa8,0x2d},{0x0d,0x86,0xbf,0xb2,0xa5,0x23},
        {0x03,0x8f,0x80,0x83,0x86,0x09},{0x01,0x8c,0x89,0x88,0x8b,0x07},
        {0x07,0x89,0x92,0x95,0x9c,0x15},{0x05,0x8a,0x9b,0x9e,0x91,0x1b},
        {0x3b,0xab,0x7c,0x47,0x0a,0xa1},{0x39,0xa8,0x75,0x4c,0x07,0xaf},
        {0x3f,0xad,0x6e,0x51,0x10,0xbd},{0x3d,0xae,0x67,0x5a,0x1d,0xb3},
        {0x33,0xa7,0x58,0x6b,0x3e,0x99},{0x31,0xa4,0x51,0x60,0x33,0x97},
        {0x37,0xa1,0x4a,0x7d,0x24,0x85},{0x35,0xa2,0x43,0x76,0x29,0x8b},
        {0x2b,0xb3,0x34,0x1f,0x62,0xd1},{0x29,0xb0,0x3d,0x14,0x6f,0xdf},
        {0x2f,0xb5,0x26,0x09,0x78,0xcd},{0x2d,0xb6,0x2f,0x02,0x75,0xc3},
        {0x23,0xbf,0x10,0x33,0x56,0xe9},{0x21,0xbc,0x19,0x38,0x5b,0xe7},
        {0x27,0xb9,0x02,0x25,0x4c,0xf5},{0x25,0xba,0x0b,0x2e,0x41,0xfb},
        {0x5b,0xfb,0xd7,0x8c,0x61,0x9a},{0x59,0xf8,0xde,0x87,0x6c,0x94},
        {0x5f,0xfd,0xc5,0x9a,0x7b,0x86},{0x5d,0xfe,0xcc,0x91,0x76,0x88},
        {0x53,0xf7,0xf3,0xa0,0x55,0xa2},{0x51,0xf4,0xfa,0xab,0x58,0xac},
        {0x57,0xf1,0xe1,0xb6,0x4f,0xbe},{0x55,0xf2,0xe8,0xbd,0x42,0xb0},
        {0x4b,0xe3,0x9f,0xd4,0x09,0xea},{0x49,0xe0,0x96,0xdf,0x04,0xe4},
        {0x4f,0xe5,0x8d,0xc2,0x13,0xf6},{0x4d,0xe6,0x84,0xc9,0x1e,0xf8},
        {0x43,0xef,0xbb,0xf8,0x3d,0xd2},{0x41,0xec,0xb2,0xf3,0x30,0xdc},
        {0x47,0xe9,0xa9,0xee,0x27,0xce},{0x45,0xea,0xa0,0xe5,0x2a,0xc0},
        {0x7b,0xcb,0x47,0x3c,0xb1,0x7a},{0x79,0xc8,0x4e,0x37,0xbc,0x74},
        {0x7f,0xcd,0x55,0x2a,0xab,0x66},{0x7d,0xce,0x5c,0x21,0xa6,0x68},
        {0x73,0xc7,0x63,0x10,0x85,0x42},{0x71,0xc4,0x6a,0x1b,0x88,0x4c},
        {0x77,0xc1,0x71,0x06,0x9f,0x5e},{0x75,0xc2,0x78,0x0d,0x92,0x50},
        {0x6b,0xd3,0x0f,0x64,0xd9,0x0a},{0x69,0xd0,0x06,0x6f,0xd4,0x04},
        {0x6f,0xd5,0x1d,0x72,0xc3,0x16},{0x6d,0xd6,0x14,0x79,0xce,0x18},
        {0x63,0xdf,0x2b,0x48,0xed,0x32},{0x61,0xdc,0x22,0x43,0xe0,0x3c},
        {0x67,0xd9,0x39,0x5e,0xf7,0x2e},{0x65,0xda,0x30,0x55,0xfa,0x20},
        {0x9b,0x5b,0x9a,0x01,0xb7,0xec},{0x99,0x58,0x93,0x0a,0xba,0xe2},
        {0x9f,0x5d,0x88,0x17,0xad,0xf0},{0x9d,0x5e,0x81,0x1c,0xa0,0xfe},
        {0x93,0x57,0xbe,0x2d,0x83,0xd4},{0x91,0x54,0xb7,0x26,0x8e,0xda},
        {0x97,0x51,0xac,0x3b,0x99,0xc8},{0x95,0x52,0xa5,0x30,0x94,0xc6},
        {0x8b,0x43,0xd2,0x59,0xdf,0x9c},{0x89,0x40,0xdb,0x52,0xd2,0x92},
        {0x8f,0x45,0xc0,0x4f,0xc5,0x80},{0x8d,0x46,0xc9,0x44,0xc8,0x8e},
        {0x83,0x4f,0xf6,0x75,0xeb,0xa4},{0x81,0x4c,0xff,0x7e,0xe6,0xaa},
        {0x87,0x49,0xe4,0x63,0xf1,0xb8},{0x85,0x4a,0xed,0x68,0xfc,0xb6},
        {0xbb,0x6b,0x0a,0xb1,0x67,0x0c},{0xb9,0x68,0x03,0xba,0x6a,0x02},
        {0xbf,0x6d,0x18,0xa7,0x7d,0x10},{0xbd,0x6e,0x11,0xac,0x70,0x1e},
        {0xb3,0x67,0x2e,0x9d,0x53,0x34},{0xb1,0x64,0x27,0x96,0x5e,0x3a},
        {0xb7,0x61,0x3c,0x8b,0x49,0x28},{0xb5,0x62,0x35,0x80,0x44,0x26},
        {0xab,0x73,0x42,0xe9,0x0f,0x7c},{0xa9,0x70,0x4b,0xe2,0x02,0x72},
        {0xaf,0x75,0x50,0xff,0x15,0x60},{0xad,0x76,0x59,0xf4,0x18,0x6e},
        {0xa3,0x7f,0x66,0xc5,0x3b,0x44},{0xa1,0x7c,0x6f,0xce,0x36,0x4a},
        {0xa7,0x79,0x74,0xd3,0x21,0x58},{0xa5,0x7a,0x7d,0xd8,0x2c,0x56},
        {0xdb,0x3b,0xa1,0x7a,0x0c,0x37},{0xd9,0x38,0xa8,0x71,0x01,0x39},
        {0xdf,0x3d,0xb3,0x6c,0x16,0x2b},{0xdd,0x3e,0xba,0x67,0x1b,0x25},
        {0xd3,0x37,0x85,0x56,0x38,0x0f},{0xd1,0x34,0x8c,0x5d,0x35,0x01},
        {0xd7,0x31,0x97,0x40,0x22,0x13},{0xd5,0x32,0x9e,0x4b,0x2f,0x1d},
        {0xcb,0x23,0xe9,0x22,0x64,0x47},{0xc9,0x20,0xe0,0x29,0x69,0x49},
        {0xcf,0x25,0xfb,0x34,0x7e,0x5b},{0xcd,0x26,0xf2,0x3f,0x73,0x55},
        {0xc3,0x2f,0xcd,0x0e,0x50,0x7f},{0xc1,0x2c,0xc4,0x05,0x5d,0x71},
        {0xc7,0x29,0xdf,0x18,0x4a,0x63},{0xc5,0x2a,0xd6,0x13,0x47,0x6d},
        {0xfb,0x0b,0x31,0xca,0xdc,0xd7},{0xf9,0x08,0x38,0xc1,0xd1,0xd9},
        {0xff,0x0d,0x23,0xdc,0xc6,0xcb},{0xfd,0x0e,0x2a,0xd7,0xcb,0xc5},
        {0xf3,0x07,0x15,0xe6,0xe8,0xef},{0xf1,0x04,0x1c,0xed,0xe5,0xe1},
        {0xf7,0x01,0x07,0xf0,0xf2,0xf3},{0xf5,0x02,0x0e,0xfb,0xff,0xfd},
        {0xeb,0x13,0x79,0x92,0xb4,0xa7},{0xe9,0x10,0x70,0x99,0xb9,0xa9},
        {0xef,0x15,0x6b,0x84,0xae,0xbb},{0xed,0x16,0x62,0x8f,0xa3,0xb5},
        {0xe3,0x1f,0x5d,0xbe,0x80,0x9f},{0xe1,0x1c,0x54,0xb5,0x8d,0x91},
        {0xe7,0x19,0x4f,0xa8,0x9a,0x83},{0xe5,0x1a,0x46,0xa3,0x97,0x8d}
};

/*********************** FUNCTION DEFINITIONS ***********************/
// XORs the in and out buffers, storing the result in out. Length is in bytes.
void xor_buf(const BYTE in[], BYTE out[], size_t len) {
    size_t idx;

    for (idx = 0; idx < len; idx++)
        out[idx] ^= in[idx];
}

/*******************
* AES - CBC
*******************/
int aes_decrypt_cbc(const BYTE in[], size_t in_len, BYTE out[], const WORD key[], int keysize, const BYTE iv[]) {
    BYTE buf_in[AES_BLOCK_SIZE], buf_out[AES_BLOCK_SIZE], iv_buf[AES_BLOCK_SIZE];
    int blocks, idx;

    if (in_len % AES_BLOCK_SIZE != 0)
        return(FALSE);

    blocks = in_len / AES_BLOCK_SIZE;

    memcpy(iv_buf, iv, AES_BLOCK_SIZE);

    for (idx = 0; idx < blocks; idx++) {
        memcpy(buf_in, &in[idx * AES_BLOCK_SIZE], AES_BLOCK_SIZE);
        aes_decrypt(buf_in, buf_out, key, keysize);
        xor_buf(iv_buf, buf_out, AES_BLOCK_SIZE);
        memcpy(&out[idx * AES_BLOCK_SIZE], buf_out, AES_BLOCK_SIZE);
        memcpy(iv_buf, buf_in, AES_BLOCK_SIZE);
    }

    return(TRUE);
}

/*******************
* AES
*******************/
/////////////////
// KEY EXPANSION
/////////////////

// Substitutes a word using the AES S-Box.
WORD SubWord(WORD word) {
    unsigned int result;

    result = (int)aes_sbox[(word >> 4) & 0x0000000F][word & 0x0000000F];
    result += (int)aes_sbox[(word >> 12) & 0x0000000F][(word >> 8) & 0x0000000F] << 8;
    result += (int)aes_sbox[(word >> 20) & 0x0000000F][(word >> 16) & 0x0000000F] << 16;
    result += (int)aes_sbox[(word >> 28) & 0x0000000F][(word >> 24) & 0x0000000F] << 24;
    return(result);
}

// Performs the action of generating the keys that will be used in every round of
// encryption. "key" is the user-supplied input key, "w" is the output key schedule,
// "keysize" is the length in bits of "key", must be 128, 192, or 256.
void aes_key_setup(const BYTE key[], WORD w[], int keysize) {
    int Nb=4,Nr,Nk,idx;
    WORD temp,Rcon[]={0x01000000,0x02000000,0x04000000,0x08000000,0x10000000,0x20000000,
                      0x40000000,0x80000000,0x1b000000,0x36000000,0x6c000000,0xd8000000,
                      0xab000000,0x4d000000,0x9a000000};

    switch (keysize) {
        case 128: Nr = 10; Nk = 4; break;
        case 192: Nr = 12; Nk = 6; break;
        case 256: Nr = 14; Nk = 8; break;
        default: return;
    }

    for (idx=0; idx < Nk; ++idx) {
        w[idx] = ((key[4 * idx]) << 24) | ((key[4 * idx + 1]) << 16) |
                 ((key[4 * idx + 2]) << 8) | ((key[4 * idx + 3]));
    }

    for (idx = Nk; idx < Nb * (Nr+1); ++idx) {
        temp = w[idx - 1];
        if ((idx % Nk) == 0)
            temp = SubWord(KE_ROTWORD(temp)) ^ Rcon[(idx-1)/Nk];
        else if (Nk > 6 && (idx % Nk) == 4)
            temp = SubWord(temp);
        w[idx] = w[idx-Nk] ^ temp;
    }
}

/////////////////
// ADD ROUND KEY
/////////////////

// Performs the AddRoundKey step. Each round has its own pre-generated 16-byte key in the
// form of 4 integers (the "w" array). Each integer is XOR'd by one column of the state.
// Also performs the job of InvAddRoundKey(); since the function is a simple XOR process,
// it is its own inverse.
void AddRoundKey(BYTE state[][4], const WORD w[]) {
    BYTE subkey[4];

    // memcpy(subkey,&w[idx],4); // Not accurate for big endian machines
    // Subkey 1
    subkey[0] = w[0] >> 24;
    subkey[1] = w[0] >> 16;
    subkey[2] = w[0] >> 8;
    subkey[3] = w[0];
    state[0][0] ^= subkey[0];
    state[1][0] ^= subkey[1];
    state[2][0] ^= subkey[2];
    state[3][0] ^= subkey[3];
    // Subkey 2
    subkey[0] = w[1] >> 24;
    subkey[1] = w[1] >> 16;
    subkey[2] = w[1] >> 8;
    subkey[3] = w[1];
    state[0][1] ^= subkey[0];
    state[1][1] ^= subkey[1];
    state[2][1] ^= subkey[2];
    state[3][1] ^= subkey[3];
    // Subkey 3
    subkey[0] = w[2] >> 24;
    subkey[1] = w[2] >> 16;
    subkey[2] = w[2] >> 8;
    subkey[3] = w[2];
    state[0][2] ^= subkey[0];
    state[1][2] ^= subkey[1];
    state[2][2] ^= subkey[2];
    state[3][2] ^= subkey[3];
    // Subkey 4
    subkey[0] = w[3] >> 24;
    subkey[1] = w[3] >> 16;
    subkey[2] = w[3] >> 8;
    subkey[3] = w[3];
    state[0][3] ^= subkey[0];
    state[1][3] ^= subkey[1];
    state[2][3] ^= subkey[2];
    state[3][3] ^= subkey[3];
}

/////////////////
// InvSubBytes
/////////////////
void InvSubBytes(BYTE state[][4]) {
    state[0][0] = aes_invsbox[state[0][0] >> 4][state[0][0] & 0x0F];
    state[0][1] = aes_invsbox[state[0][1] >> 4][state[0][1] & 0x0F];
    state[0][2] = aes_invsbox[state[0][2] >> 4][state[0][2] & 0x0F];
    state[0][3] = aes_invsbox[state[0][3] >> 4][state[0][3] & 0x0F];
    state[1][0] = aes_invsbox[state[1][0] >> 4][state[1][0] & 0x0F];
    state[1][1] = aes_invsbox[state[1][1] >> 4][state[1][1] & 0x0F];
    state[1][2] = aes_invsbox[state[1][2] >> 4][state[1][2] & 0x0F];
    state[1][3] = aes_invsbox[state[1][3] >> 4][state[1][3] & 0x0F];
    state[2][0] = aes_invsbox[state[2][0] >> 4][state[2][0] & 0x0F];
    state[2][1] = aes_invsbox[state[2][1] >> 4][state[2][1] & 0x0F];
    state[2][2] = aes_invsbox[state[2][2] >> 4][state[2][2] & 0x0F];
    state[2][3] = aes_invsbox[state[2][3] >> 4][state[2][3] & 0x0F];
    state[3][0] = aes_invsbox[state[3][0] >> 4][state[3][0] & 0x0F];
    state[3][1] = aes_invsbox[state[3][1] >> 4][state[3][1] & 0x0F];
    state[3][2] = aes_invsbox[state[3][2] >> 4][state[3][2] & 0x0F];
    state[3][3] = aes_invsbox[state[3][3] >> 4][state[3][3] & 0x0F];
}

/////////////////
// InvShiftRows
/////////////////
// All rows are shifted cylindrically to the right.
void InvShiftRows(BYTE state[][4]) {
    int t;

    // Shift right by 1
    t = state[1][3];
    state[1][3] = state[1][2];
    state[1][2] = state[1][1];
    state[1][1] = state[1][0];
    state[1][0] = t;
    // Shift right by 2
    t = state[2][3];
    state[2][3] = state[2][1];
    state[2][1] = t;
    t = state[2][2];
    state[2][2] = state[2][0];
    state[2][0] = t;
    // Shift right by 3
    t = state[3][3];
    state[3][3] = state[3][0];
    state[3][0] = state[3][1];
    state[3][1] = state[3][2];
    state[3][2] = t;
}

/////////////////
// InvColumns
/////////////////
void InvMixColumns(BYTE state[][4]) {
    BYTE col[4];

    // Column 1
    col[0] = state[0][0];
    col[1] = state[1][0];
    col[2] = state[2][0];
    col[3] = state[3][0];
    state[0][0] = gf_mul[col[0]][5];
    state[0][0] ^= gf_mul[col[1]][3];
    state[0][0] ^= gf_mul[col[2]][4];
    state[0][0] ^= gf_mul[col[3]][2];
    state[1][0] = gf_mul[col[0]][2];
    state[1][0] ^= gf_mul[col[1]][5];
    state[1][0] ^= gf_mul[col[2]][3];
    state[1][0] ^= gf_mul[col[3]][4];
    state[2][0] = gf_mul[col[0]][4];
    state[2][0] ^= gf_mul[col[1]][2];
    state[2][0] ^= gf_mul[col[2]][5];
    state[2][0] ^= gf_mul[col[3]][3];
    state[3][0] = gf_mul[col[0]][3];
    state[3][0] ^= gf_mul[col[1]][4];
    state[3][0] ^= gf_mul[col[2]][2];
    state[3][0] ^= gf_mul[col[3]][5];
    // Column 2
    col[0] = state[0][1];
    col[1] = state[1][1];
    col[2] = state[2][1];
    col[3] = state[3][1];
    state[0][1] = gf_mul[col[0]][5];
    state[0][1] ^= gf_mul[col[1]][3];
    state[0][1] ^= gf_mul[col[2]][4];
    state[0][1] ^= gf_mul[col[3]][2];
    state[1][1] = gf_mul[col[0]][2];
    state[1][1] ^= gf_mul[col[1]][5];
    state[1][1] ^= gf_mul[col[2]][3];
    state[1][1] ^= gf_mul[col[3]][4];
    state[2][1] = gf_mul[col[0]][4];
    state[2][1] ^= gf_mul[col[1]][2];
    state[2][1] ^= gf_mul[col[2]][5];
    state[2][1] ^= gf_mul[col[3]][3];
    state[3][1] = gf_mul[col[0]][3];
    state[3][1] ^= gf_mul[col[1]][4];
    state[3][1] ^= gf_mul[col[2]][2];
    state[3][1] ^= gf_mul[col[3]][5];
    // Column 3
    col[0] = state[0][2];
    col[1] = state[1][2];
    col[2] = state[2][2];
    col[3] = state[3][2];
    state[0][2] = gf_mul[col[0]][5];
    state[0][2] ^= gf_mul[col[1]][3];
    state[0][2] ^= gf_mul[col[2]][4];
    state[0][2] ^= gf_mul[col[3]][2];
    state[1][2] = gf_mul[col[0]][2];
    state[1][2] ^= gf_mul[col[1]][5];
    state[1][2] ^= gf_mul[col[2]][3];
    state[1][2] ^= gf_mul[col[3]][4];
    state[2][2] = gf_mul[col[0]][4];
    state[2][2] ^= gf_mul[col[1]][2];
    state[2][2] ^= gf_mul[col[2]][5];
    state[2][2] ^= gf_mul[col[3]][3];
    state[3][2] = gf_mul[col[0]][3];
    state[3][2] ^= gf_mul[col[1]][4];
    state[3][2] ^= gf_mul[col[2]][2];
    state[3][2] ^= gf_mul[col[3]][5];
    // Column 4
    col[0] = state[0][3];
    col[1] = state[1][3];
    col[2] = state[2][3];
    col[3] = state[3][3];
    state[0][3] = gf_mul[col[0]][5];
    state[0][3] ^= gf_mul[col[1]][3];
    state[0][3] ^= gf_mul[col[2]][4];
    state[0][3] ^= gf_mul[col[3]][2];
    state[1][3] = gf_mul[col[0]][2];
    state[1][3] ^= gf_mul[col[1]][5];
    state[1][3] ^= gf_mul[col[2]][3];
    state[1][3] ^= gf_mul[col[3]][4];
    state[2][3] = gf_mul[col[0]][4];
    state[2][3] ^= gf_mul[col[1]][2];
    state[2][3] ^= gf_mul[col[2]][5];
    state[2][3] ^= gf_mul[col[3]][3];
    state[3][3] = gf_mul[col[0]][3];
    state[3][3] ^= gf_mul[col[1]][4];
    state[3][3] ^= gf_mul[col[2]][2];
    state[3][3] ^= gf_mul[col[3]][5];
}

/////////////////
// Decrypt
/////////////////
void aes_decrypt(const BYTE in[], BYTE out[], const WORD key[], int keysize) {
    BYTE state[4][4];

    // Copy the input to the state.
    state[0][0] = in[0];
    state[1][0] = in[1];
    state[2][0] = in[2];
    state[3][0] = in[3];
    state[0][1] = in[4];
    state[1][1] = in[5];
    state[2][1] = in[6];
    state[3][1] = in[7];
    state[0][2] = in[8];
    state[1][2] = in[9];
    state[2][2] = in[10];
    state[3][2] = in[11];
    state[0][3] = in[12];
    state[1][3] = in[13];
    state[2][3] = in[14];
    state[3][3] = in[15];

    // Perform the necessary number of rounds. The round key is added first.
    // The last round does not perform the MixColumns step.
    if (keysize > 128) {
        if (keysize > 192) {
            AddRoundKey(state,&key[56]);
            InvShiftRows(state);InvSubBytes(state);AddRoundKey(state,&key[52]);InvMixColumns(state);
            InvShiftRows(state);InvSubBytes(state);AddRoundKey(state,&key[48]);InvMixColumns(state);
        }
        else {
            AddRoundKey(state,&key[48]);
        }
        InvShiftRows(state);InvSubBytes(state);AddRoundKey(state,&key[44]);InvMixColumns(state);
        InvShiftRows(state);InvSubBytes(state);AddRoundKey(state,&key[40]);InvMixColumns(state);
    }
    else {
        AddRoundKey(state,&key[40]);
    }
    InvShiftRows(state);InvSubBytes(state);AddRoundKey(state,&key[36]);InvMixColumns(state);
    InvShiftRows(state);InvSubBytes(state);AddRoundKey(state,&key[32]);InvMixColumns(state);
    InvShiftRows(state);InvSubBytes(state);AddRoundKey(state,&key[28]);InvMixColumns(state);
    InvShiftRows(state);InvSubBytes(state);AddRoundKey(state,&key[24]);InvMixColumns(state);
    InvShiftRows(state);InvSubBytes(state);AddRoundKey(state,&key[20]);InvMixColumns(state);
    InvShiftRows(state);InvSubBytes(state);AddRoundKey(state,&key[16]);InvMixColumns(state);
    InvShiftRows(state);InvSubBytes(state);AddRoundKey(state,&key[12]);InvMixColumns(state);
    InvShiftRows(state);InvSubBytes(state);AddRoundKey(state,&key[8]);InvMixColumns(state);
    InvShiftRows(state);InvSubBytes(state);AddRoundKey(state,&key[4]);InvMixColumns(state);
    InvShiftRows(state);InvSubBytes(state);AddRoundKey(state,&key[0]);

    // Copy the state to the output array.
    out[0] = state[0][0];
    out[1] = state[1][0];
    out[2] = state[2][0];
    out[3] = state[3][0];
    out[4] = state[0][1];
    out[5] = state[1][1];
    out[6] = state[2][1];
    out[7] = state[3][1];
    out[8] = state[0][2];
    out[9] = state[1][2];
    out[10] = state[2][2];
    out[11] = state[3][2];
    out[12] = state[0][3];
    out[13] = state[1][3];
    out[14] = state[2][3];
    out[15] = state[3][3];
}

std::string & aes_remove_padding(std::string & str) {
    // Trim spaces
    str.erase(std::find_if(str.rbegin(), str.rend(), std::not1(std::ptr_fun<int, int>(std::isspace))).base(), str.end());

    // Remove internal directives (ASCII ints from 0 to 31)
    auto iterator = std::find_if(str.rbegin(), str.rend(), [] (char key) {
        return key > 31;
    });

    str.erase(iterator.base(), str.end());

    return str;
}